Constant temperature refrigerator



May 26, 1936-v l.. c. BIRD ET A1.

CONSTANT TEMPERATURE REFRIGERATR Filed Aug. 15, 1935 2 sheets-sheet 1 im: M jexrde E. E715/'U 51]] n imuy.

LID Ham/U Fajah @gw WM May 26, 1936. C;- BlRD ET ALl 2,042,384

CONSTANT TEMPERATURE REFRIGERATOR Filed Aug. l5, 1935 2 Sheets-Sheet 2 (L T d a @y Ezra' Hazz 7/z7i0n M Fem-'ade F5502? ii. E715/Ups!! Patented 4May 2e, 1936 UNITED STATES v 2,042,384 CONSTANT TEMPERATURE REFRIGERATQR Lloyd C. Bird, Hampton M. Rexrode,'and Ralph R.. Chappell, Richmond, Va.,

assignors to Phipps & Bird, Inc., Richmond, Va., a corpo-s A ration of Virginia Application August 15, 1935, Serial No. 36,398

4 claims.' (o1. 257-3) This invention relates generally to apparatus for maintaining a chamber at any desired constant temperature; and, more partlcularlyfto apparatus of this character designed for -use with standard refrigerators such as are in common use for domestic purposes. i

Apparatus for maintaining a chamber at constant temperature are Well-known in this art, and

arecomparatively expensive, the cost of operation increasing with decrease in temperature.

The present apparatus is designed to maintain a chamber at a temperature of about 20 C.; and

to keep operating expense as low as possible we propose to use the common household refrigerator for the purpose of supplying cooling uid to the chamber whenever conditions require it.

The apparatus is primarily intended for us in bacteriological laboratories in which the preservation of certain materials requires normal refrigeratiorr such as is provided by the ordinary household refrigerator. By designing the 'constant temperature chamber, with its operating controls, as a simple attachment to the normal refrigerator, the expense of maintaining separate cooling units for the 20 C. chamber-is avoided;

and an extremely economical and desirable combination is produced.

Vhere the temperature .to be held constant approaches average room temperature, which in this case is about 20 cen'tigrade, the problem presented is one that involves both heating and cooling in its solution. Accordingly, the present "invention includes, as one of its elements, a heating unit adapted to be automatically operated where the temperature tends tol fall below the constant level desired. From what has been said above, it vwill b e apparent that the main object of the invention is to provide apparatus designed for use primarily in bacteriological laboratories, in which a chamber is maintained at a constant temperature by means which includes a. standard refrigerater such as is inV common use in ordinary households.

Other objects of the invention will become apparent as the detailed description thereof proceeds.

In'the: drawings: 50 Figure l is a central vertical section of one form of the apparatus, taken on the line I--I of Figure 2;

Figure 2 is a horizontal section taken on the line 2-2 of Figure 1; and 55 Figure 3 is a central vertical section through a modification of the'apparatus shown inFigures 1 and 2. f Y

InV the form'of the invention illustrated in Figures 1 and 2, the invention comprises a refrigeratorr I of the standard type', having the usual evaporator 2 suitably supported in the refrigeration `chamber 3 near the tcp thereof. So far as mere refrigeration is concerned, the struc'- tural details of the refrigerator lare not involved in the present invention, and the cooling may be effected byice or brine'or any other wellknown'equivalent of the mechanically vcontrolled evaporator illustrated diagrammatically in the drawings. v

The preferred form of the invention comprises 4 an insulated casing 4 of about the same horizontal cross-section as the casing of the refrigerator I. A strap 5 is fixed around the upper end of casing 4, and projects above the top v thereof to form a recess B in whichis' seated the lower end of the refrigerator I.

Apertures 1 and 8 extend through the bottom 9 of the .refrigerator I to receive the ducts I0 and I I, which respectively project upwardly from the top I2 and a false bottom I3 of thecasing 4. A poppet valve I4 fixed on the end of `a rod 1.5 controls the flow of cold air from the chamber 3 into the incubator chamber I6.

' The rod I5 extends through an aperture in the'guide plate I1, and has its lower end slidably and pivotally connected to the end of one arm I8 of a rocker lever, which is pivoted at its center to a bracket I9, suitably secured to the topfI2 of` the chamber IB; The other arm 20 of the rocker lever is pivoted at its outer end to a link 2 I, which at its other end is pivoted to the outer'end oi' the arm' 22 of -a rocker 23, fixed at its center to the rotor shaft 24 of a damper motorf25;v` This invention is not concerned with the structural details'of this damper motor, which is merely illustrated diagrammatically herein. These motors are old and wellknown in lair conditioning systems, andare illustrated for example, in the U. S.

Patent to vStewart,No. 1,968,325, July 3l, 1931, and i to Snediker Reissue-No. 18.875. -June-30, 1933.

The duct II extends upwardly from an aper-r ture 26 formed in the false bottom I3;v and-.aI

poppet valve 21 at the upper end of duct II controls the flow of air from a chamber 28 below the false bottom I3 and through the aperture 8 into the refrigerator chamber 3. vThe valve 21 is xed to the upper end of a rod 29 which extends through a guide 30 near the upper end of the duct Il, and which is connected pivotally at its lower end to the arm 3| of the rocker lever 23. It

that the mechanism connecting the Doppet valves I4 and 21 to the rocker lever 23 is rdesigned to open and close both valves I4 and 21 simultaneously.'

A third duct 32 extends upwardly from the false bottom I3 around an aperture 33v formed therethrough. The upper end of the duct 32 terminates a short `distance from the top I2 of vthe chamber lI6and v,isqcon'tolled by'ai poppet Vvalve 34 iixed tothe upper end oi a rod 35, extending throughthe guide 36 to be connected pivotally at its lower end to the arm 31 of a rocker lever 38, pivoted atzitscenter on a standard 38 fixed to the bottom wall of the chamben f tiallythe same as thatshown in Figure 1 oi' the drawings. In this iorm oi the invention, how- 28. A link 48 is pivotally connected 'at its opposite ends to arms 4I and 42 projecting upwardly from thecenters of the rocker levers 38 and 23,

respectively. 'I'he linkage connection is suchk that the valve 34 is closed when both valves1l4 and 21 are open, and vice versa. v y y n ,An electric heater element 43 is suitably'supported'on a bracket 44Y fixed to the bottom wall oi' the chamber 28.r A contact 45 connected to one end of the heater lelement is supported on the bracket 44 in position to; make contactwith the contact 46 suitably secured tol an arm 41.01'

the rocker lever 38, which in this case mustbe of' conducting `material. 'Ihe -current iorthe heater element is derived from a main 48 through a wire 48 tapped to-the conducting pivot of the Y rocker lever 38. A return wire 58 connects the other end of the element 43 to the main 5I 'Thecenteroithe i'alse bottom I3 is provided with an -aperture52 above a fan 53 which is mounted on the rotor shaft'of a motor 54 suit-A ably supported in the bottom.of the casing 4. The ian 53 is surrounded by a slottedcasing 55, through the slots of which airy isiorced bythe `ian in opposite directions below the false botl tom I3 to the ducts II and 32, respectively. 'I'he motor 54 `is-suitably connected to. themains 48 and 5I and is controlled by a switch 56.

A thermostatic control,-,designated generally by the Yrei'erence numeral 51, is suitably supported'on the rear wall 58 of, the chamber `=I8. This control comprises a fixed contact 58 connected to the main 48 by a wire 68. The other contact 6I of thethermostat is iixed to abimetallic strip 62, which at its lower end is suitably secured to a bracket 63 on Vthe wall 58. The'bracket 63 isv connected ,by a wire 64 to'one of theterminais 65 oithedamper motor 25, the

vother terminal 66 ofsaid motor! 25 beingconnectedgby a wire 81 to the return main 5I..

H,Asfshown in Figure loi the drawings, bothl poppet valves I4 .and 21 are open 'and the poDDet valve 34 is closed, and the heatingelement 43 `has been cut out of operation. 'I'he fan 53` draws cool air ,from ,the refrigerator chamber `3, and forces this cool air 'into the ducts II and 32.

Since the duct 32-is closed, the airfromthe fan is forced, upwardly throughithe duct II and Ainto the cooling chamber 3, while the air from the chamber 3 is drawn downwardly into thechamber I6, .untilf the temperature in chamber 3? is lowered sufilciently -to-cause; the thermostat to break circuit and fcausestoppage of the damper` f motor 25. It is to be understood that the rocker 25 ceases. When this happenathgaA link 48 swings the lever 38 'into such position as to, close the contacts 45 and 48 to energize the heater element 43. At the same time, the valve 34 is opened, and the air circulated by thefan 55 passes acrossthe heater element 43 and up the duct 32 to heat the chamber I6 until itsv temperature is raised 'suiilciently to eiTect closure of the thermostatic contacts 58 and 8|. It will be apparent from the disclosure so i'ar, that the valve 34 andthe pair of valves I4 and 21 operate inalternation to maintain the temperature withinthe chamber I8 in close approximation to the temperature desired.-

The apparatus shown in Figure 3 is substanever, the Vrefrigerator and the constant chamber are formed in a single unit. The elements corresponding to the elements oi Figures 1 .and 2 are designated by the same reference numerals primed. The operation oi' this iormof theinvention is substantially the same as that previously described,andlwill be obvious `from inspectionoi the drawings.

What we claim is: v

l. A refrigerator, a chamber, fan means for circulating a cooling uid betweenfsaid refrigerator andk chamber when thetemperature in said chamber exceeds a predetermined maximum, a second. chamber, and means in the second chamber and refrigerator operable tocut oir the said circulation of cooling iluid and` to heat the air inthe rst named chamber when the temperature thereof Afalls below-.apredetermined minimum. l. j 2. Areirigerator, a casing, a partition dividing said casing into .two chambers, aduct extendf ing into said refrigerator from one of said cham- -tending Intoy the ilrst named chamber from said ,other chamber, a heater in saidpther chamber valves controlling the iiowoi' iluid througheach of said ducts, and means controlled bythe temperature inA the iirst named chamberfor energizing said heater vand causing simultaneous opening and closing oi' the valves oi `theiirst and second ducts in alternation with the closing and opening of the valve oi' the third duct to establish and maintain a substantially constant temperature in the ilrst named chamber.

3. The apparatus,r set forth in claiml 1, in which said last mentioned means comprises a thermokstat inthe iirst named chamber, ,and mechanism controlled by the thermostat for circulating air Y between said refrigeratorand iirst named chamceeds a predetermined maximum'.

4.v 'I'he apparatus set forth in claim 1, inwhich said last .menticnedmeans comprises a thermostat in theiirst namedchamberfaheater in said.

ber when the temperature in said chamber exn Y when the temperature in the iirst named chamber falls below a predetermined minimum.

' f LLOYD C. BIRD.

HAMPTON M. .REXRODE RALPH R. CHAPPELL. 

